EUVD-2026-43798
GHSA-7p5h-m8jh-5cmq
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
DHCP replies are practically link-local so AV:A, and winning the race against the real DHCP server raises AC:H; unauthenticated with the published confidentiality-only impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Lifecycle Timeline
2DescriptionCVE.org
Integer underflow (wrap or wraparound) in Windows DHCP Client allows an unauthorized attacker to elevate privileges over a network.
AnalysisAI
Information disclosure (and vendor-labeled privilege elevation) in the Windows DHCP Client affects Windows 10 (1607/1809), Windows Server 2012 through 2025, and their Server Core installations via an integer underflow (CWE-191) reachable over the network. A remote attacker positioned to answer DHCP traffic can craft malformed responses that wrap a length/counter calculation, with a CVSS 3.1 base of 7.5 (confidentiality impact only per the published vector). …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to deliver a crafted DHCP server response to the target's DHCP Client, which in practice means being on the same broadcast/link segment or otherwise able to answer DHCP (a rogue or spoofed DHCP server, or winning a race against the legitimate one); the CVSS vector is PR:N/UI:N so no authentication or user interaction is needed once such a reply reaches the client. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The signals are moderately strong but internally inconsistent. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker on the same LAN segment (for example via a compromised host or rogue access point) stands up a malicious DHCP server or spoofs OFFER/ACK replies containing a crafted option field that underflows the client's length arithmetic. When the victim's DHCP Client parses the reply it performs an out-of-bounds read, leaking memory contents (and, if the vendor's privilege-elevation framing holds, corrupting client state). … |
| Remediation | Patch available per vendor advisory - apply the Microsoft security update referenced at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49181 for each affected OS/build; the input does not specify an exact fixed build number, so pull the correct KB per platform from that advisory rather than assuming one. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all affected systems (Windows 10 1607/1809 and Windows Server 2012-2025 across Server and Server Core editions). …
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Same weakness CWE-191 – Integer Underflow
View allSame technique Authentication Bypass
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External POC / Exploit Code
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